Process manager templating & game importing (#96)

* feat: add new template options, asahi support, and refactoring

* feat: install dir scanning, validation fixes, progress fixes, download manager refactor

This kind of ballooned out of scope, but I implemented some much
needed fixes for the download manager.

First off, I cleanup the Downloadable trait, there was some
duplication of function.

Second, I refactored the "validate" into the GameDownloadAgent,
which calls a 'validate_chunk_logic' yada, same structure as
downloading.

Third, I fixed the progress and validation issues.

Fourth, I added game scanning

* feat: out of box support for Asahi Linux

* fix: clippy

* fix: don't break database

src-tauri/src/error/process_error.rs

@@ -6,7 +6,6 @@ use serde_with::SerializeDisplay;
 pub enum ProcessError {
     NotInstalled,
     AlreadyRunning,
-    NotDownloaded,
     InvalidID,
     InvalidVersion,
     IOError(Error),
@@ -20,7 +19,6 @@ impl Display for ProcessError {
         let s = match self {
             ProcessError::NotInstalled => "Game not installed",
             ProcessError::AlreadyRunning => "Game already running",
-            ProcessError::NotDownloaded => "Game not downloaded",
             ProcessError::InvalidID => "Invalid game ID",
             ProcessError::InvalidVersion => "Invalid game version",
             ProcessError::IOError(error) => &error.to_string(),